Helical Andreev bound states and superconducting Klein tunneling in topological insulator Josephson junctions

Article

关键词: TRANSPORT;    SYMMETRY;    SURFACE;   

DOI  :  10.1103/PhysRevB.88.075401

来源: SCIE

【 摘 要 】

Currently, much effort is being put into detecting unconventional p-wave superconductivity in Josephson junctions based on topological insulators (TIs). For that purpose we propose to use superconducting Klein tunneling, i.e., the reflectionless passage of Cooper pairs through a potential barrier in a gated ballistic junction. This phenomenon occurs due to the fact that the supercurrent is carried by helical Andreev bound states (ABSs) characterized by spin-momentum locking similar to the normal-state carriers. We derive the spectrum of the helical ABSs and the corresponding Josephson current for a junction made on the surface of a three-dimensional TI. The superconducting Klein tunneling is predicted to yield a nonsinusoidal current-phase relation and an anomalous critical current I-c that does not vanish with increasing barrier strength. We also analyze the dependence of the IcRn product (where R-n is the normal-state junction resistance) on the microscopic parameters of the superconductor/TI interface, which leads to lower IcRn values than expected from previous models of the proximity-effect Josephson junctions.

【 授权许可】

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